During the geomechanical study of a subsurface, cores are conventionally collected from the subsurface in order to acquire rock samples.
The determination of certain geomechanical parameters of the rocks provides insight into the behavior of the underground structure when considering exploitation of the subsurface.
Some of these geomechanical parameters, such as the angle of friction (Φ) or the cohesion (C) of the Mohr-Coulomb criterion that characterizes the failure threshold of the rock, are parameters used in all geomechanical studies at different scales, for example for a well, reservoir, cover, or oil field.
Usually, determination of the angle of friction and cohesion of a rock requires triaxial compression tests at different confining pressures.
Although they provide satisfactory results, these triaxial compression tests are complex to carry out, particularly for shale because of the cracks caused by drilling and storage (dehydration). In addition, these tests take a very long time, at least a week per test.
There is therefore a need for a method for determining geological parameters from a rock sample, including the angle of friction and cohesion of the rock, that is simpler and faster to implement than existing methods.